1. Field of the Invention
This invention relates to an adjustable steering column mechanism which can provide height adjustment of the steering wheel in a motor vehicle.
2. Disclosure Information
Various mechanisms have been proposed which provide height adjustment of the steering wheel in tiltable steering column assemblies of automotive vehicles. For example, British Patent Specification 2,191,273, corresponding to U.S. Pat. No. 4,732,050, shows a mechanism in which matingly engageable toothed plates provide a locking mechanism to lock the steering column in a variety of different positions. However, the specification fails to teach any means of biasing the toothed surfaces apart when adjustment is desired. The construction shown in this specification does not allow a smooth adjusting action because when the mechanism is released, the mating plates are not separated.
U.S. Pat. No. 4,541,298, assigned to the assignee of the present invention, discloses a height adjusting apparatus having a support for rotatably carrying a steering column member and a bracket carrying the support. The support moves relative to the bracket in two mutually perpendicular directions. The mounting assembly further includes a clamping device for clamping the bracket to the support, characterized in that two rack and pinion sets are connected between the bracket and the support such that movement of the support relative to the bracket in each of the mutually perpendicular directions causes the pinions to roll relative to the racks of the respective rack and pinion sets. The clamping device increases the frictional forces opposing the relative movement of the rack and pinion.
British patent application 2,217,817, corresponding to U.S. Ser. No. 07/606,241, filed by the assignee of the present invention on Oct. 31, 1990, now U.S. Pat. No. 5,074,586, discloses a steering column construction wherein the height and reach adjustment are provided by a single lever arm. The apparatus includes a cam wall against which the lever operates to lock the steering column into a desired position. The '817 apparatus does not rely on matingly engageable teeth to provide a positive lock of the steering column in a desired position.
Various other height adjusting mechanisms have been proposed which utilize matingly engageable teeth to lock or unlock the position of the steering column to achieve a desired position. For example, British Patent No. 1,018,485, and U.S. Pat. No(s). 4,041,796; 4,078,448; 4,102,218; 4,463,626; 4,472,982; 4,530,254; 4,594,909; and 4,938,093 all disclose mechanisms which rely on the mating engagement of teeth to achieve a desired height position of the steering wheel. However, all of the mechanisms rely on an external spring attached to a component within the steering column to provide a biasing force to either clamp or unclamp the mating teeth.
It is an advantage of the present invention to provide a height adjusting apparatus wherein a pair of matingly engageable teeth sets cooperate to lock the steering column in a desired height position and wherein one set of the teeth includes an integrally formed biasing means to unclamp the teeth when adjustment is desired and eliminate a need for relying on external springs.
These and other advantages, objects and features of the present invention will become apparent from the summary, drawings, detailed description and claims which follow.